$90 up front could definitely scare away some of the one or two time racers. Keep the option to just buy it once, but much like the transponders, have the club buy a bunch of them to rent out at a certain amount per race. Eventually, the club can make money off of them once the startup cost is paid off.

The WKA does not allow any form of communication with the driver. If you are talking about communication from the tower only, that might be possible, but everyone must then have a radio for it to work properly.